When I bought my Acekard 2i it was just that, but now it's called the Acekard 2i 3DS, will this new card work the same as my original Acekard 2i? I need a second one for my Mum and she has a DSi XL like me.

Perhaps you are new to the scene but the Acekard 2i can have bootloader updates thus allowing it to work on multiple device. For example, the AK2i was originally designed to work on the DSi but a bootloader update allowed it to run on the 3DS as well later down the line.

I suggest to buy from a site within your country unless you don't mind waiting a long time for Hong Kong-based companies to ship it to the UK in exchange for a cheaper price. Look at Acekard's official trusted sites list here